(1) Field of the Invention
The present invention relates to a process for the preparation of polyacetylene having a high electroconductivity. Polyacetylene prepared by the process of the present invention can be widely used for a battery material, an electric part material and other electronic materials.
(2) Description of the Related Art
The synthesis of polyacetylene has long been investigated, and the process using a Ziegler-Natta catalyst, proposed by Shirakawa et al, is the most popular known process [see, for example, J. Polym. Sci Polym. Ed., 12, 11 (1974)]. Japanese Unexamined Patent Publication No. 59-51904 discloses a process in which polyacetylene having an electroconductivity of 2.times.10.sup.3 S/cm is prepared by the steps of heat-treating (hereinafter referred to as "aging") a Ziegler-Natta catalyst at 20.degree. to 100.degree. C. in an organic solvent, polymerizing acetylene using this catalyst, and then doping iodine into the formed polymer.
Furthermore, from Synthetic Metals, 17, 241 (1987), a process is known in which polyacetylene having an electroconductivity of 4.8.times.10.sup.3 S/cm is obtained by polymerizing acetylene in a liquid crystal solvent by using a Ziegler-Natta catalyst, and doping iodine into the formed polymer.
Moreover, in Synthetic Metals, 22, 1 (1987), a process is reported in which polyacetylene having an electroconductivity of 2.times.10.sup.4 S/cm is synthesized by heat-treating a Ziegler-Natta catalyst at 120.degree. C. in a silicone solvent, polymerizing acetylene by using the formed catalyst solution, and then doping iodine in the formed polymer In this process, if a reducing agent such as butyl lithium is incorporated just before the polymerization, a polymer having such a high electroconductivity as about 1.times.10.sup.5 S/cm can be obtained. However, the incorporation of a reducing agent such as butyl lithium is complicated, and therefore, a simpler process is desired.